Internal Neurolysis with and without Microvascular Decompression for Trigeminal Neuralgia: Case Series

The efficacy and safety of gabapentin vs. carbamazepine in patients with primary trigeminal neuralgia: A systematic review and meta-analysis

Background

Drug therapy is the most commonly used treatment for primary trigeminal neuralgia (PTN), in which carbamazepine is the first-line drug. Recently, the anti-epileptic drug gabapentin has also been widely used in patients with PTN, but whether it can be used as a substitute for carbamazepine still needs to be verified. Our study aimed to assess the safety and efficacy of gabapentin vs. carbamazepine as a treatment for PTN.

Methods

We searched seven electronic databases for studies published as of 31 July 2022. All randomized controlled trials (RCTs) of gabapentin vs. carbamazepine on patients with PTN that met the inclusion criteria were included. Meta-analysis was conducted using Revman 5.4 and Stata 14.0, in which forest plots, funnel plots, and sensitivity analysis were performed. Mean difference (MD) and odds ratio (OR) with 95% confidence intervals (CIs) were used for the measurement indicators of continuous and categorical variables, respectively.

Results

A total of 18 RCTs with 1,604 patients were eventually identified. The meta-analysis showed that compared with the carbamazepine group, the gabapentin group significantly improved the effective rate (OR = 2.02, 95% CI 1.56 to 2.62, P < 0.001), reduced the adverse event rate (OR = 0.28, 95% CI 0.21 to 0.37, P < 0.001), and improved the visual analog scale (VAS) score (MD = -0.46, 95% CI -0.86 to -0.06, P = 0.03). Although the funnel plot showed evidence of publication bias, the sensitivity analysis revealed the stability of the results.

Conclusion

The current evidence showed that gabapentin may be superior to carbamazepine in relation to efficacy and safety in patients with PTN. It is crucial that more RCTs are conducted to confirm the conclusion in the future.

Short-lasting unilateral neuralgiform headache attacks (SUNCT/SUNA): a narrative review of interventional therapies

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and short-lasting unilateral neuralgiform headache with autonomic symptoms (SUNA) are disabling primary headache disorders. The advent of advanced imaging technologies and surgical techniques has translated to a growing arsenal of interventional therapies capable of treating headache disorders. This literature review sheds light on the current evidence available for interventional therapies in medically intractable SUNCT/SUNA. PubMed and EMBASE were searched for publications between 1978 and 2022. Inclusion criteria were SUNCT/SUNA studies reporting outcomes following occipital nerve stimulation (ONS), pulsed radiofrequency (PRF) of sphenopalatine ganglion (SPG), stereotactic radiosurgery (SRS), deep brain stimulation (DBS) or microvascular decompression (MVD) of the trigeminal nerve. A greater than 50% reduction in severity or a greater than 50% reduction in the number of attacks was defined as a successful response. The rate of successful responses for the various treatment modalities were as follows: ONS 33/41 (80.5%), PRF of SPG 5/9 (55.6%), DBS of the ventral tegmental area 14/16 (86.7%), SRS to the SPG and/or trigeminal nerve 7/9 (77.8%) and MVD 56/73 (76.7%). Mean follow-up time in months was 42.5 (ONS), 24.8 (PRF), 25.3 (DBS), 20.8 (SRS) and 42.4 (MVD). A significant proportion of SUNCT/SUNA patients remain refractory to medical therapy (45%-55%). This review discusses existing literature on interventional approaches, including neuromodulation, radiofrequency ablation, gamma knife radiosurgery and MVD. The outcomes are promising, yet limited data exist, underscoring the need for further research to develop a robust surgical management algorithm.

Internal neurolysis versus intraoperative glycerin rhizotomy for trigeminal neuralgia

OBJECTIVE

Internal neurolysis (IN) and intraoperative glycerin rhizotomy (ioGR) are emerging surgical options for patients with trigeminal neuralgia without neurovascular contact. The objective of this study was to compare the neurological outcomes of patients who underwent IN with those of patients who underwent ioGR.

METHODS

The authors retrospectively reviewed all patients who underwent IN or ioGR for trigeminal neuralgia at our institution. Patient demographic characteristics and immediate postoperative outcomes, as well as long-term neurological outcomes, were compared.

RESULTS

Of 1044 patients who underwent open surgical treatment for trigeminal neuralgia, 56 patients underwent IN and 91 underwent ioGR. Of these 147 patients, 37 had no evidence of intraoperative neurovascular conflict. All patients who underwent IN and 96.7% of patients who underwent ioGR had immediate postoperative pain relief. At last follow-up, patients who underwent IN had lower Barrow Neurological Institute (BNI) pain intensity scores (p = 0.05), better BNI facial numbness scores (p < 0.01), and a greater degree of pain improvement (p = 0.05) compared with those who underwent ioGR. Patients who underwent IN also had significantly lower rates of symptomatic pain recurrence (p < 0.01) at last follow-up over an average of 9.5 months.

CONCLUSIONS

IN appears to provide patients with a greater degree of pain relief, lower rates of facial numbness, and lower rates of pain recurrence compared with ioGR. Future prospective studies will better characterize long-term pain recurrence and outcomes.

Delayed pain relief in patients with trigeminal neuralgia following microvascular decompression: A single-central retrospective study

Background

Compared to hemifacial spasm after microvascular decompression (MVD), delayed relief (DR) rarely occurs in patients with trigeminal neuralgia (TGN).

Objective

To analyze the characteristics of post-MVD DR in TGN patients to provide useful clues for the clinical differential diagnosis of postoperative DR.

Methods

The clinical data of all patients with TGN who underwent MVD in our center from January 1, 2016, to December 31, 2020, were reviewed retrospectively.

Results

In 272 TGN MVD patients, DR occurred in nine patients (3.3%) during the follow-up periods of 1–6 years. During surgery, all nine DR-TGN patients were identified as having neurovascular conflicts (NVCs), involving the offending artery (OA) in eight patients (two OAs in two patients) and both an artery and a vein in the other patient. The compression site was near the root entry zone (REZ) in most DR patients (7/9). Delayed relief was relieved in seven patients within 5 days after surgery and within 30 days in the other two patients. No recurrence or serious complications were observed within the mean 4 (1-6)-year follow-up duration.

Conclusion

Delayed relief rarely occurs in TGN patients after MVD. Neurovascular conflicts located at the REZ and NVC of grade III may be two important factors contributing to DR in TGN patients. Delayed relief may occur when the pain gradually improves after the operation and responds effectively to a small dose of carbamazepine. The recurrence rate of TGN seems even lower in such patients.

Internal Neurolysis for the Treatment of Trigeminal Neuralgia: A Systematic Review

INTRODUCTION

Trigeminal neuralgia (TN) remains a challenging disease with debilitating symptoms and variable efficacy in terms of treatment options. Microvascular decompression (MVD) with internal neurolysis (IN) is an alternative treatment that might benefit patients but has limited understanding. We performed a systematic review of IN for the treatment of TN.

METHODS

Studies from 2000 to 2021 that had assessed IN for TN were aggregated and independently reviewed.

RESULTS

A total of 520 patients in 12 studies were identified, with 384 who had undergone IN (mean age, 53.8 years; range, 46-61.4 years; mean follow-up, 36.5 months). Preoperative symptoms had been present for ∼55.0 months before treatment, and pain was predominantly in V2 and V3 (26.8%), followed by other distributions. Of the patients, 83.7% (range, 72%-93.8%) had had an excellent to good outcome (Barrow Neurological Institute pain scale score [BNI-PS], I-II). The pain outcomes at 1 year were excellent for 58%-78.4%, good or better for 77%-93.75%, and fair or better for 80%-93.75% of the patients. On average, facial numbness after IN was experienced by 96% of the patients. However, at follow-up, facial numbness remained in only 1.75%-10%. Most of the remaining numbness was not significantly distressing to the patients. Subgroup comparisons of IN versus recurrent MVD, IN versus radiofrequency ablation, the effects of IN in the absence of vascular compression, and IN with and without MVD were also evaluated.

CONCLUSIONS

IN represents a promising surgical intervention for TN in the absence of vascular compression and for potential cases of recurrence. Complications were limited in general but require further study.

Trigeminal Neuralgia: Current Approaches and Emerging Interventions

Trigeminal neuralgia (TN) has been described in the literature as one of the most debilitating presentations of orofacial pain. This review summarizes over 150 years of collective clinical experience in the medical and surgical treatment of TN. Fundamentally, TN remains a clinical diagnosis that must be distinguished from other types of trigeminal neuropathic pain and/or facial pain associated with other neuralgias or headache syndromes. What is increasingly clear is that there is no catch-all medical or surgical intervention that is effective for all patients with trigeminal neuralgia, likely reflective of the fact that TN is likely a heterogenous group of disorders that jointly manifests in facial pain. The first-line treatment for TN remains anticonvulsant medical therapy. Patients who fail this have a range of surgical options available to them. In general, microvascular decompression is a safe and effective procedure with immediate and durable outcomes. Patients who are unable to tolerate general anesthesia or whose medical comorbidities preclude a suboccipital craniectomy may benefit from percutaneous methodologies including glycerol or radiofrequency ablation, or both. For patients with bleeding diathesis due to blood thinning medications who are ineligible for invasive procedures, or for those who are unwilling to undergo open surgical procedures, radiosurgery may be an excellent option-provided the patient understands that maximum pain relief will take on the order of months to achieve. Finally, peripheral neurectomies continue to provide an inexpensive and resource-sparing alternative to pain relief for patients in locations with limited economic and medical resources. Ultimately, elucidation of the molecular mechanisms underlying trigeminal neuralgia will pave the way for novel, more effective and less invasive therapies.

Long Time Efficacy and Safety of Microvascular Decompression Combined with Internal Neurolysis for Recurrent Trigeminal Neuralgia

Objective

To explore the clinical efficacy and safety of microvascular decompression (MVD) combined with internal neurolysis (IN) in the treatment of recurrent trigeminal neuralgia (TN) after MVD.

Methods

Sixty-four patients with recurrent TN admitted to the hospital from January 2014 to December 2017 were divided into two groups according to the surgical method. Twenty-nine patients, admitted from January 2014 to December 2015, were treated with MVD alone, whereas 35 admitted from January 2016 to December 2017 were treated with MVD+IN. The postoperative efficacy, complications, and pain recurrence rate of the two groups were analyzed.

Results

The efficacy of the MVD+IN and MVD groups were 88.6% and 86.2%, and the cure rates were 77.1% and 65.5% respectively. There was no statistically significant difference between the two groups (p>0.05). The cure rate (83.3%) of patients in the MVD+IN group, who were only found thickened arachnoid adhesions during the operation that could not be fully released, was significantly higher than that of the MVD group (30.0%) (p<0.05), while the efficacy (91.7% vs. 70%) of the two groups was not statistically different (p>0.05). For patients whose arachnoid adhesions were completely released, there had no significant difference (p>0.05) in the efficacy (87% vs. 94.7%) and recurrence rate (5.0% vs. 11.1%). The incidence of postoperative facial numbness (88.6%) in the MVD+IN group was higher than that in the MVD group (10.3%) (p<0.01). The long-term incidence of facial numbness was not statistically significant (p>0.05). In the 18–36 months follow-up, the recurrence rate of patients in the MVD+IN group (9.7%) and in the MVD group (16%) were not statistically different (p>0.05).

Conclusion

A retrospective comparison of patients with recurrent TN showed that both MVD and MVD combined with IN can effectively treat recurrent TN. Compared with MVD alone, MVD combined with IN can effectively improve the pain cure rate of patients with recurrent TN who have only severe arachnoid adhesions. The combination does not increase the incidence of long-term facial numbness and other complications.

External Neurolysis in Microvascular Decompression for Magnetic Resonance Imaging-Negative Idiopathic Trigeminal Neuralgia

OBJECTIVE

Internal neurolysis has been proposed as an alternative to microvascular decompression in patients with idiopathic trigeminal neuralgia (TN) in whom neurovascular compression is not confirmed by magnetic resonance imaging (MRI). External neurolysis, which straightens and realigns the trigeminal nerve root axis by dissecting the arachnoid membranes around the nerve, was reported 20 years ago in the context of so-called negative exploration when MRI did not confirm the absence of the offending vessel, but is not currently used.

METHODS

External neurolysis was performed in 4 patients with idiopathic TN with typical evoked neuralgic pain despite the absence of suspected offending vessels on MRI. The surgical findings that caused TN were summarized and the outcomes were evaluated using the Barrow Neurological Institute Pain Intensity Scale (BNI-PS).

RESULTS

Tethering and distortion of the nerve root by surrounding arachnoid membranes were commonly found. All 4 patients showed complete pain relief immediately after surgery. During the follow-up period of 26.5 ± 16.92 months (±standard deviation), 3 of 4 patients had no pain (score I, BNI-PS). One patient received a score of IIIa on the BNI-PS assessment. There was no instance of recurrence or side effects associated with the surgery.

CONCLUSIONS

Idiopathic TN can be induced by individual variation of the surrounding inner arachnoid membranes supporting the trigeminal nerve root, and the condition cannot be identified by MRI. Intradural external neurolysis may be considered an effective treatment for MRI-negative idiopathic TN.

Young-onset trigeminal neuralgia: a clinical study and literature review

OBJECTIVE

Trigeminal neuralgia (TN) primarily occurs in elderly adults and is thought to be induced by neurovascular compression. However, a few children and young adults may present with the clinical features of TN. In this study, we aim to retrospectively assess the data of young patients with TN from a single center.

METHODS

Of 783 consecutive patients with TN treated at our center between 2007 and 2017, 11 young patients under the age of 30 years with TN met the inclusion criteria and were enrolled. Their clinical records, surgical treatments, and long-term outcomes were obtained and analyzed.

RESULTS

All the 11 patients with TN underwent microvascular decompression (MVD). The average age at symptom onset was 24 years (range, 14-29 years), and the average age at the time of surgery was 28.9 years (range, 25-35 years). Further, 5 patients had left-sided symptoms, and 6 had right-sided symptoms. Surgery revealed only venous compression in 3 patients, only arterial compression in 5 patients, and both venous and arterial compression in 3 patients. The average duration of symptoms was 4.9 years, and the average follow-up duration was 7.4 years (range, 4.5-12.9 years). The long-term outcome was excellent in 9 patients and good in 2 patients, and there were no long-term complications.

CONCLUSIONS

The symptoms and surgical findings presented in this cohort for young-onset TN are similar to those reported in elderly adults. MVD appears to be a safe and effective treatment for young patients with TN.